If this happened i EVERYDAY usage then people would be complaining about this EVERYDAY, as a matter of fact there would probably be returns because of this issue EVERYDAY.
Sorry mate, I still feel that your plucking at straws, trying to find anything wrong with your new shiny device, and what you have found in my opinion isn't a problem, if it was then we would all be agreeing with you.
It's the nature of mass market digital products:
- Many people may never watch much video on their iPads.
- Beyond that, some people may never watch videos that cause the contrast/brightness to get crazy. (For example, it happens for me in almost every film I watch, but almost none of the YouTube videos I routinely watch.)
- Finally, some people just aren't super attentive about stuff like this - and it appears to use an algorithm based on some kind of short rolling average of what's on the screen, so the transition is usually smooth and minor over time.
It's not an elitist thing. It's not "I don't think my super duper expensive device should be flawed, Apple has lost me as a customer." It's just incredibly annoying for the letterboxes to turn gray when I'm trying to waste time watching Pirates of the Caribbean.